Heating and humidifying apparatus



' Aug. 2, 1949. H. M. E. GEHRKE HEATING AND HUMIDIFYING' APPARATUS 3 Sheets-Sheet l Filed Feb. 27, 1947 l @il 'NIMH Will...

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Filed Feb. 27, 1947 H. M. E. GEHRKE 2,477,734

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Patented ug. 2, 1949 UNITED STATES PATENT OFFICE 2,477,734 HEATING AND HUMIDIFYING APPARATUS Henry M. E. Gehrke, Chicago, Ill.

Application February 27, 1947, Serial N o. 731,345

7 Claims.

My invention relates to heating and humidifying apparatus and in particular to a compact unit which may be installed within a room or space to heat the air therein to the desired temperature and to maintain proper humidity conditions within the room or space.

1t is the principal object of my invention to provide an improved unit space heater and humidifier which wil1 maintain the air temperature and the humidity within the space at predetermined or desired levels.

Another object of the present invention is to provide an improved unitary space heater and humidier which is compact, pleasing in appearance and extremely efficient in operation.

Another object of the present invention is to provide an improved hot Water heater and humidier which may be constantly and automatically supplied with the water necessary for its operation.

Another object is to provide an improved room heater and humidifier which gives a more uniform operation than those heretofore developed.

Still a further object of the present invention is to provide a room heater and humidier of the hot water type which is safe in its operation and has a minimum of operating parts.

Other objects of the invention will become apparent from the following description taken in connection with the .accompanying drawings in which:

Fig. 1 is a medial, longitudinal cross-sectional View of my novel heater and humidiiier with a portion of the apparatus shown in elevation;

Fig. 2 is a cross-sectional view taken substantially along the line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is an elevational View of the heater and humidifier on a greatly reduced scale, looking at the apparatus from the righthand side of Fig. l; and

Fig. 4 is a diagram of a preferred electrical circuit forming a part of this apparatus.

Referring primarily to Figs. 1 and 2, my improved heater and humidiiier includes a tank l forming a boiler Iwhich contains a quantity of liquid, generally water, to be heated. The tank i0 comprises a cylindrical Wall I2 and a pair of end walls I4 and I5 which are welded around their peripheral edges to the cylindrical wall I2 to form a fluid-tight tank. A plurality of heatradiating ns I8 are mounted on the exterior surface of the cylindrical Wall I2 and may have a generally rectangular form as shown in Fig. 2. The heat-radiating iins may be mounted on 2 the cylindrical wall I2 by having the cylindrical wall pressed outwardly or expanded against the plurality of iins i8 while the latter are held in a jig. I prefer to iill the spaces between adjacent fins with metal foil or shavings 2@ to increase the heat radiating surface.

A second pandike tank 22 is mounted on the upper edges of the iins I8. The tank 22 is secured in place and prevented from accidental dislodgment by a pair of mounting plates 24 which are welded at 26 to the end Walls '28 of the tank 22 and are secured to the end pair of the radiating iins I8 by suitable sheet metal screws 3G. The tank 22 forms the humidifier portion of my apparatus as will hereinafter appear.

The tanks I0 and 22 are interconnected by means of a short conduit or pipe 32 which eX- tends from the -bottom of the tank 22 to the top of the boiler tank 1G. The conduit 32 may be brazed or welded to the cylindrical wall I2 of the boiler tank i9 and to bottom wall 34 of the tank 22. The boiler tank l@ is illed by iirst introducing liquid into the humidifier tank 22 and allowing it to run through the interconnecting conduit 32 into the boiler tank l0. When the boiler tank !U has been completely filled with water, the tank E2 is then filled with water to the desired level.

During the operation of my heater the interconnecting conduit 32 also serves as an equalizer to relieve any pressure which may tend to form within the boiler tank Ill. Thus, it is not necessary to construct the boiler tank I so that it Will be required to withstand any substantial pressures.

At times it may be desirable to drain my apparatus completely of water or the operating liquid, and for that purpose I provide a drain valve 36 of well known type which is mounted in the Wall I6 at the bottom of the boiler tank I0.

The tanks I8 and 22 are mounted within a housing 38 which comprises a front Wall 40, a rear Wall 42 and end Walls 44 and 4B. A removable top cover 48 closes the top of the housing. The walls and cover are preferably made of sheet metal and the walls may lbe secured together at the corners of the housing by Welding or by sheet metal screws. The air to be heated is admitted into the housing through openings 50 at the bottom of the front and rear walls 40 and 42 and circulates into the space or room being heated through an outlet 52 in the upper portion of the front Wall 4. The effective size It of the outlet opening 52 may be controlled by suitable adjustable louvres 54 which are pivotally mounted in angle brackets 55 lat either side of the opening 52.

The boiler tank l is supported on a pair of mounting b-locks 56 which rest on a pair of angle members 60 which are secured as by spot welding to the front and rear walls 48 and 42. Each mounting block 58 has a generally rectangular shape and is provided in its upper edge with a semicircular cutout portion 62 which embraces the outer surface of the wall |2, thereby holding and supporting the boiler tank l0 in the housing 38. The mounting blocks 58 maybe additionally supported within the housing by means of screws which extend through the walls of the housing into the blocks. In order to .give added rigidity to the assembly, screws 64 may be used to secure the blocks 58 to the end iins of the heat radiating ns i8.

The water is heated by an electric heating element 6.6 which may beof any suitable type. The `one which I have shown in the drawings is a .dual immersion unit electric heater of the type `manufactured by -General Electric Company which can be connected to .give varying heat outputs. The heating element 66 preferably lextends the length of the boiler tank |0 so as to obtain a more rapid heating of the liquid contained within the tank. The element 66 is proyvided at one end with a `pipe thread 68 which is threaded -tightly into a union 'lll which is in turn welded at l2 to the end wall I4 of the tank thus insuring that all connections are water-tight.

' In Iorder eifectively to control the operation of the heater and of the heating element 66, I provide a dual aquastat 14 which may be of the "type manufactured by the White-Rodgers Electric Compa-ny of St. Louis, Missouri. The aqua- .stat i4 includes a pair of heat responsive elements 'I6 and 18 contained within a tube 80 which extends into the interior of the boiler tanklll. T-he tube 88 is provided with a pipe thread 82 which is screwed into a union 84 which is in turn welded to the end wall i4 at 86 Vjust above the union 10. The heat responsive elements 16 and 18, responsive to the temperature of the liquid in the boiler Vtank I8, operate a pair of switches 88 and 80 (Fig. 4) respectively, the operation of which will be explained hereinafter.

In order to promote the circulation of air through the housing 38 and over the fins i8 and metal foil or shavings 20, I provide a blower or fan 82 including a small electric motor 84. 'Ihe Vmotor 94 is secured to the under side of the cover 48 by a suitable bracket 96 which is bolted to the motor 84 by bolts 88 and to the cover by a bolt |08. The operation of the blower or fan 82 will be explained hereinafter in connection with the explanation of the electric circuit.

Water may be supplied to the humidifier tank 22 through a pipe |82 which is connected to a low pressure source. If no low pressure source is available it may be connected to a pressure reducing valve of any well known type which willreduce the pressure from the regular city water main `to that which is suitable for supplying water to my improved heater and humidifier. The pipe |02 extends through the end wall 46 of the housing and the end wall 28 of the tank 22 and terminates in an upwardly extending portion |04 having a valve seat |86. A valve member |08 cooperates with the valve seat to controlthe dow of water from the pipe |82 into the humidifier tank 22. The valve |08 is operated bp a float ||0 pivotally mounted at ||2 to a standard ||4 secured on the bottom of the tank 22. The float ||0 insures that the Water level in the tank 22 may be maintained substantially constant. If it is not convenient to connect the heater and humidier to provide for the automatic supply of water the humidifier tank 22 may be filled by hand by removing the top closure 48. All that is necessary is that a constant supply of Water be maintained withi-n the tank 22 to insure that the boiler tank I0 is completely filled with water.

Referring primarily to Fig. 4, the heater is connected to the usual household electric power Vsupply line .I I6, IIB; and a master on-oif switch .|20 is provided in the side ||6 of the line. Conductor |22 connects one side of the heating element 66 to .theline 2| I6 While conductor |24 conducts .the other side of the heating element 66 to contact |26 of a relay operated switch |28. The other contact |30 of the relay operated switch |28 'is connected to `the line I8 by va conductor |32.

The primary |34 of a step-down transformer |36 is connected across the line ||6. ||8; the secondary |38 `of the transformer |36 hasone side thereof connected in series by means of a conductor |40 to a relay |42 which operates the switch 28. The other side of the transformer secondary is vconnected to a terminal |44, and the relay |42 is connected to another terminal |46. The step-down transformer |36, 'the relay |42 and the relay operated switch |28 are enclosed in a housing |748 and are made asa unit which may -be purchased from the White-Rodgers Electric Company of St. Lou-is, Missouri.

The terminal |46 is connected by a conductor |48 to the switch 88 which is `connected in series by conductor to room thermostat |52, the room thermostat in turn being connected by conductor |54 to the terminal |44. This room thermostat |52 may be of any suitable adjustable type but Ipreier to use one which is manufactured by White-Rodgers Electric Company of St. Louis,

' Missouri.

As previously noted, the closing and opening of the switch 88 is controlled by a heat responsive element T6. 4The temperature range within which the switch 88 is closed and opened may be regulated by a suitable regulating dial 56 which forms a part of the dual aquastat 14 (Fig. 3).

Assuming that it is desired to maintain the water temperature between 175 F. and 195 F., with the line switch |20 closed, the limit switch 88 of the aquastat '|4 will close if the water temperature Vdrops below 175 F. If the room temperature is below that desired, the thermostat |52 also closes or will be closed. This completes the circuit through the transformer secondary |38 and the relay |42, the circuit being: secondary |38, conductor |40, relay |42, terminal |46,

conductor |48, switch 88, conductor |58, room thermostat |52, conductor |54, terminal |44, and back to the secondary |38. Energizing the relay |42 closes the switch |28 which then connects the heating element across the line H6, ||8 in the following manner: line H6, switch |20, conductor |22, heating element 66, conductor |24, contact |26, switch |28, contact |38, conductor |32 and line |18. The heating element will heat the water .contained within the boiler tank l0 until it reaches `the desired temperature of F. at which time the switch at 88 will open thereby breaking the secondary transformer circuit to deenergize the relay |42 and to open the switch |28. When the switch |28 opens, the circuit to the heating element 6B is broken and is, therefore, deenergized. The limit aquastat switch 88 thus prevents overheating of the heater.

The second switch 98 in the dual aquastat I4 controls the operation of the ian or blower motor 94. It is not desirable that the fan or blower circulate air across the boiler tank I0 and radiating ns I8 unless the water contained therein is at a predetermined temperature. Consequently, it is usually desirable to set the operation of the heat responsive element 'I8 by means of the dial |58 so that the switch 90 closes when the water in the tank I0 reaches a temperature somewhat higher than 175 as, for example, 180 F. or 185 F. When the water has reached this temperature the heat responsive element 18 closes the switch 90. The switch 90 is connected by means of conductor |68 to one side of the fan motor 94 and by a conductor |62 to the line I I8; the fan motor 94 is connected to the line IIS by a conductor |54. When the switch 90 closes, it closes the circuit including line IIB, switch |20, conductor |64, motor 94, conductor I 68, switch 90g conductor |62, and line I I8. Ii the temperature of the water in the boiler tank Ill falls below a predetermined value and it is undesirable to circulate air across the tank II] and radiating iins I8, the heat responsive element I8 will open the switch 9o to break the circuit to the fan motor a4. The operation of the blower is independent of the room thermostat |52, but operation of the room thermostat switch is dependent upon room temperature which is in turn a function of the amount of heated air circulated by the blower. Thus the operation of the heater is actually dependent upon the load imposed by the space being heated. It will be seen from the foregoing description of the operation of my improved heater and humidiiier that it is possible to maintain the temperature in the room within a predetermined range because overheating is prevented by connecting the room thermostat |52 in series with the limit aquastat switch 88 and by connecting the fan aquastat 98 so that its operation is independent of the room thermostat |52 but is dependent upon the temperature of the `water in the boiler tank I8. I have found from experience that the limit switch 88 closes before the room thermostat |52 so that the circuit controlling the operation of the heating element G6 is conditioned for operation when the room temperature requires raising.

The humidity of the air is maintained substantially constant because the circulating heated air passes over the humidier tank 22 which contains a quantity of water at all times. This water is heated somewhat by means of the interconnecting conduit 32 which provides communication between the water in the boiler tank I0 and that in the humidifier tank 22; positioning the tank 22 immediately above the boiler I0 and in contact with the heat radiating fins I8 also aids in heating this water.

I do not advise heating the temperature of the water in the boiler tank I8 above the boiling point of water, i. e., above 212 F., because I have found that more uniform heat conditions can be obtained if this Water temperature is maintained within the range of 175 F. to 195 F. Furthermore, by keeping the temperature of the water below the boiling point I do not generate any steam which would bubble through the interconnecting conduit 32 to cause splashing of the water in the tank 22 or the introduction of steam into the circulating air. It will be observed that the heater is extremely eicient in its operation because all of what might at nrst appear to be heat losses, that is, the heating of the housing, etc., actually results in the heating of the air which is circulated in the room in which the heater is installed; consequently, the eliciency of this heater is extremely high.

While I have illustrated but a single embodiment of the present invention, it will be obvious to those skilled in the art that numerous modifications can be made therein without departing from the spirit and scope of my invention, and I, therefore, desire to be limited only by the scope of the appended claims.

What I desire to claim as new and secure by United States Letters Patent is: y i. [i space heater and humidifier comprising in combination, a tank forming a boiler and adapted to contain a liquid to be heated, a plurality of heat radiating ns mounted on said boiler tank, an electric heating element mounted in said boiler tank and adapted to be connected to a source oi electric power so as to heat liquid contained within said boiler tank, a second tank mounted on the upper edges of and in heat exchange relation with said heat radiating ns and adapted to contain a quantity of liquid to humidiiy the air circulating over said fins, a conduit interconnecting said second tank and said boiler tank so that liquid will flow from said second tank into said boiler tank until said latter tank is iilled, and an aquastat including an element responsive to the temperature of the liquid in said boiler tank and a switch opera-ted thereby, said switch being connected in series with the source of electric power and arranged to control the operation of said heating element, whereby the temperature oi the liquid in said boiler tank may be maintained within a predetermined range.

2. A space heater and humidifier comprising in combination, a tank forming a boiler and adapted to contain a liquid to be heated, a plurality of heat radiating iins mounted on said boiler tank, an electric heating element mounted in said boiler tank and adapted to be connected to a source of electric power so as to heat liquid contained within said boiler tank, a second tank mounted on the upper edges of and in heat eX- change relation with said heat radiating fins and adapted to contain a quantity of liquid, a conduit interconnecting said second tank and said boiler tank so that liquid will flow from said second tank into said boiler tank until said latter tank is iilled, a room thermostat responsive to the temperature of the space being heated, an aquastat including an element responsive to the temperature of the liquid in said boiler tank and a switch operated thereby, and a circuit connecting said room thermostat and said switch in series and in series with the source of electric power and arranged to control the operation of said heatingv element, whereby the temperature of the air in the space being heated may be maintained within a predetermined temperature range.

Y 3. A space heater and humidiiier comprising in combination, a tank forming a boiler and adapted to contain a liquid to be heated, a plurality of heat radiating iins mounted on said boiler` tank, a heating element mounted in said boiler tank and adapted to heat liquid contained therein, a second tank mounted on the upper edges of and in heat exchange relation with said heat radiating ns and adapted to contain a4 quantity of liquid, said second tank being positioned in the ow path of the air circulating over aumen said boiler andf said fins, aiconduit interconnecting said. secondl tank and said boiler` tank sol that liquid will ilow` from rsaidsecondi-tank into said boiler tank until said'latter` tank islled, a blower for. :circulating air over said fins and past said second tank, a housing enclosing-l said.- tanks and said blower, means containedV wiizl'iinsadv housing for supporting said tankswithin saidl housing, and` means responsive to the temperature oi`V the liquid` in said boiler tank ior controlling the operation of said heating element so that the liquid temperature may bemaintained within a predetermined temperature range.

4. A space heater Vand humidifier comprising inv cor nation, a tank forming a boilerY and adapte-i to conta-in a-l-iqnid tobeheatedf, aY plurality of heat radiating fins mounted on said boiler tank, a heating element mounted in said boiler tank and adapted to heat liquidv contained therein, a second tank mounted on the upper edges of and in heat exchange relation with said heat radiating iins and adapted to contain a quantityl oi liquid, said second tank being positioned in the flow path of the air circulating over said boiler and said fins, ablower for ycir-cul'ati-rigv air over said boiler and said iins and past said second tank, an inlet pipe for said second tank, a valve for regulating the flow of liquid from said inlet pipe, float `means responsive to the liquid level in said second tank controlling the operation of said valve thereby to maintain the liquid insaid second tank at a predetermined level, a conduit interconnecting said second tank and said boiler tank so that liquid wiil iiowfrom said second tank into said boiler tank until said latter tank is iled, and means responsive to the temperature of the liquid in said boiler tank forv controlling the operation ofrsaid heating element sothat the liquid temperature may be maintained within a predetermined temperature range.

5. A space heater and humidier comprising in combination, a tank forming aboiler and adapted to contain a liquid to be heated, aplurality ci heat radiating` nns mounted on said boiler tank, an electric heating element mounted in said boiler tank and adapted to berconnected to a source of electric power so as to heat liquid contained within said boiler tank, a second tank mounted on the upper edges of and in heat exchange-relation with said heat radiating ns and adapted to contain a quantity of liquid, a conduit interconnecting said second tank and said boiler tank so that liquid will flow from said 'second tankinto boiler tank until said lattertank is lled,

an electric motor driven blower adapted to circulate air over said heat radiating fins and past said second tank, a housing enclosing said tanksv andA said blower, and an ac 'uastat'includingY a pair of elements responsive to the temperature oflthe liquidin said boiler tank and a pairoi switches, each operated by one of said elements, one ofsaid switches b-eing connected so as to control the operation of said heating element so that the liquid temperature may be maintainedwithin a predetermined temperature range andthe other or said .switches being connected in series withl saidbiower motor to controi the operation thereofv` according to the temperature of the liquid contained within said boiler tank.Y

5; A space heater and humidifier comprising in combination, a tank forming a boiler and adapted to contain water to be heated; a plurality oi heat radiatingnns mounted onsaid boiler tank, aia-electric heatingfelement Vmounted in said'l boiler. tank and adapted tobefconnectcdeto a source of: electric power so as toA heat the water contained within said boiler tank, a second and open top tank mounted' on the upper edges of Vand in` heat exchange relation with said heat radiating iii-is and adapted to contain a quantity of water for hum-idifying the circulating air, a conduit interconnecting said humidifier tank and said boiler tank sovthat water will iiow from said humidier tank into said boiler tank until said latter tank is filled, an electrically operated blower adapted to promote circulation of air over said heat radiating iins and past said humidier tank, a housing enclosing said tanks and said blower and having inlet and outlet openings, an aquastat including an element responsive tothe temperature of the water in said boiler tank and a switch operated thereby, a circuit connecting saidV switch in series with the source oi electric powery and arranged" to control the operation of said heating element whereby the temperature of the water in said boiler tank may be maintained within a predetermined range, and' said aquastat also including a second element responsive to the temperature of the water in said boiler tank and a switch operatedl thereby, said' last mentioned switch beingI connected in series with said blowerl and the source or' electric power to control the operation of4 said blowerl 7. AV space heater and humidi'er comprising incombination, a tankV forming a boiler and adapted to contain water to be heated', a pluralityfofheat radiating iins mounted on said boiler tank', an electric heating element mounted in said boiler tank and adapted to be connected to a source oi eiectric power so as to-Aheat the water containedl within said boiler tank, a second tank mounted onthe upper edges of and in heat. exchange relation with saidV heat 'radiating ns Vand adapted toY contain a quantity of water ior humidiiying'the circulating air,` a conduit interconnecting said humidifier tank and said boiler tank'so that water will flow fromV said humidifiertank into said boiler tank until said latter tank is lled', an; electrically operated blower adapted to promote circulation oi air over said heat radiating ns and past said humidifier tank, a housing` enclosing said tanks and said. blower and having inlet and outlet openings, an aquastat including a pair of elements ,responsiver to the temperature of the water in said' boiler tank and a pair of switches, each operated byv one of said elements, a room thermostat responsiveto thetemperature of the air in the space being heated, a circuit connecting said room thermostat and one of said switches in series and in Aseries with the source of electric power and arranged to control the operation of said heating element whereby the temperature oi the air in the space being heated may be maintained within a predetermined range, anda second circuitconnecting, the other of said switches in vseries with said blower and the source of electric power.

HENRY M. E. GEHRKE.

REFERENCES CTED The following referenlces are of record in the le oi this patent:

UNTED STATES PATENTS 'Number Name. Datey 1,476,441- Dion Dec. 4, 1923 1,788,515, Gannon Jan. 13, 1931 2,151,140 Novak Mar. 21, 1939 2,360,071 Nol1. Oct. 10,1944 

